Hi,
since I added `ywrap' parameter in my lilo.conf's 'video=vesa:ywrap', I
have notice strange behaviour: every now and then my screen get shifted
downwards by two lines (which makes bottom lines unreadable, as they are
"off the screen" then). After awhile those two lines dissapear and
everything comes back to normal. That happens quite regularly, so I
expect some cycle.
The kernel documentation says this:
<snip>
You can pass options to vesafb using "video=vesa:option" on
the kernel command line. Multiple options should be separated
by comma, like this: "video=vesa:ypan,invers"
Accepted options:
invers no comment...
ypan enable display panning using the VESA protected mode
interface. The visible screen is just a window of the
video memory, console scrolling is done by changing the
start of the window.
pro: * scrolling (fullscreen) is fast, because there is
no need to copy around data.
* You'll get scrollback (the Shift-PgUp thing),
the video memory can be used as scrollback buffer
kontra: * scrolling only parts of the screen causes some
ugly flicker effects (boot logo flickers for
example).
ywrap Same as ypan, but assumes your gfx board can wrap-around
the video memory (i.e. starts reading from top if it
reaches the end of video memory). Faster than ypan.
<snip>
...has it anything to do with video memory and mtrr settings? To speed
things up, I'm using following command to set mtrr's (this is copied
from X settings; `mtrr' parameter passed to framebuffer driver was
setting my card as 4MB and it is 8MB):
#
# set MTRR registers
# now, this is supposed to speed thing up - while in console (X sets this by
itself)
#
echo "base=0x40000000 size=0x800000 type=write-combining" >| /proc/mtrr
I wouldn't like to resign from `ywrap' options: it's fast and I'm
working in "text mode" (sic! as this is fb after all :-) a lot.
Big thanks in advance,
--
Lukasz
